Prokaryotes

Chapter 19

Prokaryotes! • The small wonder… First inhabited

the earth ____________!• Continued to rule alone for 1.5 billion

years until they gave rise for more complex organisms

• Still exist today (bacteria) and are still one of the most fierce predators, as well as important helpers associated with human health.

• Have ____________• Even though they are in ________

_____________________they are very similar in morphology

• Generally single celled

Y. pestis (cause of bubonic plague)

ESCHERICHIA COLI is a type of bacteria that lives in the intestinal tract, aiding the digestive process by suppressing the growth of harmful bacteria and synthesizing vitamins

Prokaryotes are broken into two major groups… diverged a long time ago

Archaea• Has its ______________

____________(some match Eukaryotes)

• Use ________________ ____________similar to eukaryotes

• _____________________• Some Carbon chains,

mostly branched

Bacteria• Has unique rRNA

sequences• Replicates with _______

____________________• ______________________

_______________cell wall (Gram Stain)

• Unbranched carbon chains in the membrane lipids

Prokaryotes are divided by the way they get nourishment

• Earliest life needed to be autotrophs (make their own food). Need Energy (make ATP… to do so they need a carbon source!)– Photoautotrophs: Energy from

______________… carbon from _______ (Cyanobacteria… No Archaea just bacteria)

– Chemoautotrophs____________________________ and break their bonds for energy… get their carbon from ______ (many Archaea metabolize this way)

More Prokaryote divisions• Once some Autotrophs existed

organisms can start eating other organisms (_________________)– Photoheterotrophs: Energy from

___________, Carbon from ________ _________________ (some purple and green bacteria)

– Chemoheterotrophs: Get energy by _________________________, also get their carbon from _____________ ______________ (similar to animals… largest group, includes E. coli and SOME Archaea)

Purple bacteria

Anthrax (Bacillus anthracis )

Archaea

Archaea are found in unusually harsh environments

• Very similar to Eukaryotes in many of their DNA sequences

• Can obtain nutrients in the same ways and be the same size as bacteria

• Resemble ancient life because they live in environment close to the original earth’s environment– Extreme halophiles: Live in

______________________ like the dead sea

– Extreme thermophiles: Live in _____________________

– Methanogens: Live without oxygen and _________________

Bacteria

Bacteria come in 3 basic shapes• Spherical shaped (Cocci), often in

clumps (streptococcus: strep throat)• Rod-Shaped (often called _________)

and live singularly… not touching • Curved or Spiral shaped (vibros,

spirilla or ______________). Syphilis is caused by a spirochete

Some bacteria cause disease... • Any disease causing agent is called a

_______________________• Half of human diseases are caused by

pathogenic bacteria• Classified into two mechanisms– ___________ Producing: • Bacteria ________________ that is

pathogenic – usually VERY dangerous… just a little

infection can kill you) – Ex: Clostridium botulinum

– _________________Producing:• Bacteria themselves _____________

_____________________________– generally more mild but do include

major illness like food poisoning and typhoid fever

Vibrio cholerae causes a life-threatening diarrhea using both endo and exo toxins

Virulence and Prevention• Virulence of a pathogen is

measured by LD50… the amount of pathogen that will kill 50% of those exposed to it

• The __________________________ __________________________and dangerous the microbe.

• With bacteria most treatments are _______________ and the best way to prevent onset is with good _______________________

The Komodo dragon carries at least 3 strains of highly virulent bacteria in its mouth…this way it __________________________ ____________________________

Current uses for Bacteria• Biological warfare: Not a new

idea… – during the Middle Ages plague

victims were used as ‘bombs’ and tossed into enemy lines

– Europeans unknowingly and knowingly gave bacterial (and viral) infections to the people they were trying to concur (Yellow fever and the American Indians ring a bell?)

– US started using researching anthrax, as well as botulism back in 1943• Now this bioterrorism is becoming a

threat to the US… Anthrax easily spreads and aerosolizes

Not all bacteria are bad! (Bioremediation)• Cleaning the environment: Bacteria

can also be used for good– Used to ______________________

_____________________(clean out septic tanks and help keep pipes flowing)

– ____________________(there are natural bacteria that metabolize oil waste and they can be cultivated to clean up habitats that have been damaged by humans)

It’s diversity that helps prokaryotes continue to survive

• Unique structural features that allow prokaryotes to make up for their small singular size…– Prokaryotic ____________

(allows for locomotion)– _________(allows for adhesion

to a favorable environment)– _____________ : Resting

structure for bacteria in an unfavorable environment… lets it hang out until conditions get better (used like seed in plants)• Clostridium and Bacillus

anthraces form endospores

Eukaryotes

Chapter 20

Review

• Prokaryotes: Domains Archaea and Bacteria

• Protista: The Junk Kingdom• Fungi• Plantae• Anamalia

Before the Final

Right Now

In the beginning (or a couple million years later)

• Eukaryotes evolved from prokaryotes using a couple cool features

1. Membrane infolding…When the ________________________ ___________________________________________ (like ER)

2. ______________________… One cell living within another, benefiting both (like Mitochondria and chloroplasts)

Do you have a junk drawer?• The protista are a junk kingdom… which is really probably a lot

of kingdoms• They are placed together because they don’t fit in the other

kingdoms, not because they have something in common.• They can be classified by how they look– but DNA doesn’t

always agree

Ancient Protists

Fungus- like Protists

Plant- like Protists

Animal- like Protists

For now we’ll go with this

• Protista is broken into 3 major groups based on their lifecycle… most groupings are non-monophylogenetic.– Diploid dominant (like animals)– Alternation of generations (like plants)– Haploid/ gametophyte dominant (like fungi)**Note– these are not evolutionary linages

Dominant Diploid Generation• Diploid dominant… heterotrophic

and sometimes parasitic– Flagellates: __________________,

include Giardia which lives in the intestine, and Trypansoma which lives in the blood and causes African sleeping sickness

– Shelled Amoebas: Secrete a shell then extend their ______________ (fake feet)out to move, they also use them for endocytosis

- Alveolates... Next page

Giardia

Dominant Diploid Generation… continued

Alveolates• Apicomplexa: specialized with

complex organelles for being a ___________________. Include Plasmodium which causes malaria• Ciliates: Move via cilia. Have 2

kinds of nuclei (1 macro and several micro) ______________ ______________________. Live in aquatic environments• Some _____________: Although

they ARE alveolates we will discuss them with Algae because most are photosynthetic

Alternation of Generations

• When a species alternates LIVE GENERATIONS.

• It lives _____________ ___________________

• Plants have distinct alternations… so do these next protista

Unicellular Algae• Act like single celled plants…

(photosynthetic, autotrophic)… not a monophyletic group

• Dinoflagellates: distinct look per species. Two flagella that cause them to spin around. _________________________________________and can be deadly. (some _________)

• Diatoms: Huge marine food source. Have a shell made of __________ (look glassy). Float near the surface of the ocean

• Green Algae: single celled, multiple life stages… more to come

More on Green Algae• ______________________________

__________________________________________________________________________________________

• Their early evolution can be ‘seen’ in modern species– Chlamydomonas seems to be the

precursor to Volvox.– When Volvox reproduces the cells

that leave (red or green biflagellate cells) look like those of Chlamydomonas.

– When Volvox is in its growth state it appears as an aggregation of those same Chlamydomonas - like cells

Multicellular Algae• Most complex algae…

– ______________________________________________________________________________________________________

• Brown algae (not all brown) ______________ _________________________, diverged from diatoms. Form large kelp forests that are indispensable to fish, otters and even gray whales (have “hold fasts” instead of roots)

• Red Algae: can __________________. Life in tropical waters and play an important role in reef building (have unicellular members– dinoflagellates)

• Multicellular green algae: _____________ ___________________(like many plants do). This is a cycle of haploid and diploid organisms being formed

Cellular Slime Molds• Gametophyte dominant• Unicellular and multicellular life

stages• _____________________________

___________________________… making them fungus-like

• CASE EXAMPLE: Dictostelium– Feeds on bacteria… if they are plentiful

it leads a happy solitary, single celled (amoeboid) life. Reproducing by mitosis and moving very little.

– When bacteria is scarce the _______ ______________________________ (using cAMP signals) to form a colony with more motility.

– Moves to what it thinks might be a better place __________________ ______________________________ (the colony differentiates its cells… crazy)